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Inclusion rating of steels as per ASTM standads

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Inclusion rating of steels as per ASTM standads.
All procedure and comparison charts are provided.

Publicada em: Engenharia, Tecnologia, Negócios

Inclusion rating of steels as per ASTM standads

  2. 2. INCLUSIONS ▪ Inclusions are non metallic particles embedded in the steel matrix. ▪ Chemical compounds of metals like (Fe, Mn, Al, Si, Ca etc) with non metals (O, S, N, C, H) ▪ Examples: SiO2,MnO,MgS,Ce2S3,AlN etc… ▪ Properties: An inclusion is a mismatch with the steel matrix. Both may have different properties resulting in undesired effect.
  3. 3. INCLUSION RATING ▪ Standard reference charts depicting a series of typical inclusion configurations (size, type, and number) were created for direct comparison with the microscopic field of view ▪ Rating is done in comparison with the ASTM standard chart. [Designation: E 45] ▪ Inclusions are assigned to a category based on similarities in morphology, that is, by size, shape, concentration, and distribution, and not necessarily on their chemical identity
  4. 4. CLASSIFICATION OF INCLUSIONS ▪ Inclusions are classified into four categories (called Type) based on their morphology ▪ Each of them are classified into two subcategories based on their width or diameter
  5. 5. CLASSIFICATION OF INCLUSIONS categories A-Sulfide Type heavy thin B-Alumina Type heavy thin C-Silicate Type heavy thin D-Globular Oxide Type heavy thin • Although the categories contain chemical names that imply knowledge of their chemical content, the ratings are based strictly on morphology • The four categories, or Types, are partitioned into Severity Levels based on the number or length of the particles present in a 0.50 mm2 field of view
  6. 6. CLASSIFICATION OF INCLUSIONS ▪ Type A and C inclusions are very similar in size and shape ▪ They are distinguished based on their colour when viewed under brightfield illumination ▪ Type A-Sulfide are light gray ▪ Type C-Silicate are black ▪ The B-type stringers consist of a number (at least three) of round or angular oxide particles with aspect ratios less than 2 that are aligned nearly parallel to the deformation axis ▪ The D-type are globular in shape
  7. 7. PROCEDURE ▪ The minimum polished surface area of a specimen for the microscopic determination of inclusion content is 160 mm2 (0.25 in.2) ▪ Field of view is 0.50 mm2 or square of side 0.71 mm ▪ Either of two techniques may be employed to achieve a 0.50 mm2 field of view ▪ One method is to project the microscope image onto a viewing screen that has a square mask with 71.0 mm sides drawn on it ▪ Another option is to use a reticle made for the microscope, which will superimpose the required square mask directly onto the field of view
  8. 8. PROCEDURE ▪ Inclusions are classified into the before mentioned four types ▪ After the inclusions are categorized by Type, they must be categorized by thickness or diameter- thin and heavy series ▪ After classification by type and thickness, the severity levels are determined for the inclusions comparing with the chart ▪ These values can be numerically calculated as length or number based on the limits given in standard Table (given below)
  9. 9. COMPARISON CHART- A (Sulfide type)
  10. 10. COMPARISON CHART- B (Aluminate type)
  11. 11. COMPARISON CHART- C (Silicate type)
  12. 12. COMPARISON CHART- D (Globular type oxides)
  13. 13. PROCEDURE
  14. 14. REFERENCES ▪ R E SMALLMAN – Modern Physical Metallurgy and Materials Engineering ▪ P C ANGELO – Materials Characterization ▪ ASTM E 45 – 05 - Standard Test Methods for Determining the Inclusion Content of Steel ▪ ASTM E 1245 - Practice for Determining Inclusion or Second-Phase Constituent Content of Metals by Automatic Image Analysis